In recent years, multidisciplinary investigations of developmental processes have provided evidence suggesting that electric and magnetic fields play an important role in cell and tissue behavior. In U.S. Pat. No. 4,818,697, entitled, "Techniques for Enhancing the Permeability of Ions," the disclosure of which is incorporated herein by reference, a method and apparatus are disclosed by which transmembrane movement of a preselected ion is magnetically regulated using a time-varying magnetic field. The fluctuating magnetic field is tuned to the cyclotron resonance energy absorption frequency of the preselected ion. And in U.S. Pat. No. 4,932,951, entitled "Method and Apparatus for Controlling Tissue Growth and An Applied Fluctuating Magnetic Field," the disclosure of which is incorporated herein by reference, a method and apparatus are disclosed whereby the growth characteristics of target tissue can be influenced by exposing the target tissue, especially bone tissue, to a magnetic field with precise predetermined ratios of frequency to average magnetic flux density. These important discoveries brought to light the interplay of local geomagnetic fields and frequency dependence in ion transport mechanisms.
In the present invention, a magnetic field is used to stimulate the production of growth factor in vivo. The growth factors produced can, by stimulating cell growth and cell replication, exert a beneficial and continuing influence after removal of the magnetic field.
Growth factors have long been recognized as potent molecules that can increase the proliferation of many cellular types of living tissue. These growth factors have been identified and produced in-vitro. The problems associated with the delivery of the in-vitro produced growth factor to a specific site in a living organism has limited the use of growth factors as a therapeutic tool.
It has now been found that the production of growth factor can be increased in vivo by the exogenous stimulation of living tissue with magnetic fields. In effect, the existing cells are stimulated to increase the intracellular synthesis of growth factor and/or decrease the intracellular synthesis of growth factor inhibitors by the applied magnetic field. The net effect is an increase in the amount of effective growth factor available to influence cell growth and proliferation and, therefore, a net increase in the amount of mitogenic cellular activity. The increased level of growth factor, in turn, results in increased levels of cell production and proliferation. This increased rate of cell growth results in increased rates of cell repair, regeneration and/or remodeling in the local area of interest. When applied to a damaged area of tissue, the present invention allows for an increased rate of repair or healing using the cells' natural regenerating and repair capabilities.